Adjustable tension capstan



y 1, 1952 H. M. STEPHENSON 2,601,961

v ADJUSTABLE TENSION CAPSTAN Filed March 9, 1951 19 "'19 20 2/ k j Inventor Hugh M. Stephenson HS Abtorneg.

Patented July 1, 1952 ADJUSTABLE TENSION CAPSTAN Hugh M. Stephenson, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Application March 9, 1951, Serial No. 214,819

2 Claims.

This invention relates to a tensioning device for ribbon-like materials and especiallyto such a device which is adapted for use in imparting tension to a moving glass fibre insulated rectangular conductor without damaging the insu l'ation. 1

The need for such a device has often arisen in the spooling and winding of coils of heavy rectangular conductors but nodevice which would supply a tension on such conductors without damaging the insulation has been available. The woven glass insulation would be severely dam aged by previously used tensioning devices so that an expensive varnish coating was required before" glass insulated conductor wire could be spooled for transportation or used in winding" coils.

magnetic material as a force transmitting medium between the movable and stationary parts of the device. I

Further objects and advantages of this invention will become apparent and this invention will be better understood by reference to the accompanying drawing and description, and the features' of. novelty which characterize this invention will' be pointed outwith particularity in the claims: annexed hereto.

In accordance with the broadaspects of this invention, a spool, or drum, is rotatably mountedona shaft which is threaded into an openingin a supporting plate. The drum contains a permanent magnet and provides, with the supportingv structure, a closed flux path for the field of the permanent magnet. The end of the drum adjacent to the supporting structure is separated therefrom by a gap. This-gap contains a finely divided magnetic material which tendsto couple thei drum. to" the supporting structure because of the-fluxifrom the permanent magnet. The width of the gap is adjustable to provide means for varying the retardingforceon the spool. Ari'ng' surrounding the drum and keyed thereto for rotation liesin a plane which is at an adjustable cent the ring. Thering is' adapted to slide the I strand sideways during each revolution anamount dependent upon its angle with the plane of rotation of the drum. The strand is wrapped around the drum a sufficient number of times to prevent slippage. The device is adjustable for different tensions and diiierent wire sizes.

In the drawing, Fig. 1 is an isometric view of a device embodying my invention; and Fig. 2 is a cross-sectional view through the center of the drum of the device shown in Fig. 1.

Referring to the drawing, I have shown a vertical supporting structure I formed of a magnetic material. Formed integrally with this supporting structure is a base 2 which may be of any desired shape. Supporting structure I is provided with a threaded aperture 3 in which externally threaded stud 4 is secured. Stud 4 is secured against rotation by lock nut 5 and serves as a shaft for cylindrical drum or spool 6 which is rotatably mounted thereon by means of a nonmagnetic bearing 1. Bearing l is provided with a cutout annular portion which serves as a reservoir for oil or other lubricant.

The drum 6 is formed of a magnetic material and is open at one end to accommodate a nonmagnetic'spacer'ring 9 and an axially polarized permanent magnet ring I 6. Both rings 9 and I U are inserted in drum 6' by means of a force fit. An end flange H is secured to the closed end of drum 6 by means of a plurality of screws l2. Positioned in the bore of bearing 1 adjacent end flange l l are a plurality of thrust washers l 3 whichserve to space end flange H from the end of shaft 4.

Surrounding the outer substantially cylindrical surface l 4 of the drum 6 is a fleeting ring l5 to which is secured a key [6 which slidingly engages a slot I! of drum 6. Key it prevents relative rotation of fleeting ring l5 and drum 6. Fleeting ring I5 is disposed at an angle to the plane. of "rotation of the drum. This angle is maintained by means of two sets of ballbearing rollers- I 8 which are secured by means of bolts l9 to slotted flanges 20. While only one set of ball bearing rollers I8 is shown in Fig. 1, a second set (shown in Fig. 2) is offset from the vertical center line of the drum symmetrically to the set shown in Fig. 1. Flanges 20 are in turn fastened to the supporting plate I by any suitable means as, for example, screws 2|. An additional ball bearing roller 22 is disposed at the top of the drum. Roller 22'is supported by an adjustable mounting 23 which is inserted in a slotted groove 24 in supporting plate I. A bolt 33 which is' provide'd with a lock nut 34 is threaded Referring to Fig. 2, a gap 36 is provided between the drum 6 and the supporting structure i. Positioned in this gap is a finely divided magnetic material, such as soft iron powder. This magnetic material is adapted to produce a force transmitting connection between supporting structure I and drum 6 when under the influence of a magnetic field. It will be observed that the flux of permanent magnet i is provided with a magnetic circuit which passes through supporting structure I and drum 6 as indicated on Fig. 2. The flux, in following this path, crosses and recrosses gap 36 to cause the magnetic medium 3'! to serve to transmit force between supporting structure I and drum 6.

The amount of force thus transmitted is proportional to the width of the gap. It will be observed that shaft 4 bears against the thrust washers l3 and is threaded into supporting structure I. By threading the shaft 4 toward the right, as shown in Fig. 2, the air gapwill be widened. This provides a method of adjustment of the tension on the strand 3| as it leaves the capstan. Threaded into shaft 4 is a crank 38 which engages the end flange II of the drum 3 and provides a quick release of the tension on strand 3| without changing the adjustment provided by threaded shaft 4. Such a device is advantageous when changing reel or splicing strand 3 I.

No seals are necessary to retain the finely divided magnetic material 31 in the gap. In operation any magnetic particles which would tend to drop out of the gap are prevented from doing so by the lines of magnetic flux which attract them back toward the magnet. Since this capstan is designed to operate normally in the range of 500 R. P. M., the centrifugal force tending to throw the particles outwardly is insufficient to do so. Of course, this centrifugal force would become a factor in very high speed operation of this device.

The operation of the device is as follows:

As a strand 3!, which may be any type of ribbon-like material, such as a woven glass covered conductor approaches the drum 5 from any suitable source of supply (not shown), it is guided by rollers and 21 which are adjusted to accom modate the strand. Spring 29 biases roller 21a toward roller 21b to insure initial contact between the strand 3! and the surface I4 of the drum. A force in the direction of arrow is drawing the strand from the drum 6. The strand 3! is engaged by fleeting ring l5 and pushed sidewise an amount equal to the offset of the fleeting ring from the plane of rotation. When properly adjusted, this amount is equal to or slightly greater than the width of the conductor thus it can be seen that the fleeting ring clears that portion of the outer surface of drum 6 which is T necessary for the accommodation of the segment of the strand 3i approaching drum 6. If the strand 3! is a woven glass insulated conductor, the sidewise motion will not harm the insulation because the motion is in the direction in which the insulation is wound. By varying the gap 36, the tension may be varied. Likewise, the device may be made to accommodate various widths of strands by the adjustment of rollers 25 and screw 33.

It is now apparent that I have provided an adjustable tension device which will impart a tension on a moving strand of wire without any damage to the insulation of the wire. It is further apparent that I have provided such a device utilizing a magnetic medium as a force transmitting device in such a manner that the tension imparted to the moving strand is easily and accurately adjustable.

Various modifications of this device will occur to those skilled in the art. While I have illus trated and described one particular embodiment of this invention I wish it to be understood that this invention is not restricted to the specific embodiment shown and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A capstan adapted to impart a tensioning force to a moving strand comprising a supporting structure having an opening formed therein, a shaft mounted in said opening, a spool member formed of magnetic material rotatably mounted on said shaft and spaced from said supporting structure defining a gap, said spool having a substantially cylindrical outer surface about which said strand is adapted to be wound in frictional engagement therewith, a finely divided magnetic material in said gap, a source of magnetic fiux associated with said spool and operable to solidify said finely divided magnetic material whereby said finely divided magnetic material tends to couple said spool to said supporting structure, said shaft being arranged for longitudinal movement in said opening, said spool having means engaging said shaft whereby longitudinal movement of said shaft longitudinally moves said spool to vary the Width of said gap thereby to vary the tension force on said strand as it leaves saidspool, means for selectively securing said shaft in a predetermined position thereby to set the width of said gap and said tension force at a predetermined value, said shaft having a longitudinal opening formed therein, and a member arranged for longitudinal movement in said shaft opening, said member being arranged to engage said spool thereby to longitudinally move the same away from said support ing structure increasing the width of said gap whereby quick release of said tension force is provided. I

2. A capstan adapted to impart a tensioning force to a moving strand comprising a supporting structure having a threaded opening formed therein, a shaft having a portion threadingly mounted in said opening for longitudinal movement with respect to said supporting structure, a spool member formed of magnetic material rotatably mounted on said shaft and spaced from said supporting structure defining'a gap, said spool having a substantially cylindrical outer sur-= face about which said strand isadapted to be wound in frictional engagement therewith, a finely divided magnetic material in said gap, a sourceof magnetic flux associated with said spool and" operable to solidify said finely divided magnetic material whereby said finely divided magnetic material tends to couple said spool to said sup.-

porting structure, said spool having means engaging said shaft whereby longitudinal movement thereof longitudinally moves said spool to vary the width of said gap thereby to vary the tension force on said strand as it leaves said spool,

means for selectively securing said shaft a predetermined position thereby to set the width of said gap and said tension force at a predetermined value, said shaft having a longitudinal opening formed therein having threads formed throughout at least part of its length, and a member arranged for longitudinal movement in said shaft opening and having a portion threadingly engaging said shaft opening threads, said member being arranged to engage said spool thereby to longitudinally move the same away from said supporting structure responsive to longitudinal movement of said member whereby the width of said gap is increased to provide quick release of said tension force without disturbing said predetermined gap setting.

HUGH M. STEPHENSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 578,099 Hanson Mar. 2, 1897 1,333,691 Weiss Mar. 16, 1920 1,954,499 Snyder et a1 Apr. 10, 1934 2,519,882 Bullard et al Aug. 22, 1950 2,544,360 Schmidt Mar. 6, 1951 2,557,140 Razdowitz June 19, 1951 2,575,360 Rabinow Nov. 20, 1951 OTHER REFERENCES 20 1949, pp. 16-2-0. (Copy inDiv. 68.) 

